Plate type heat exchanger



Oct. 19, 1965 H. R. OTTO 3,212,572

PLATE TYPE HEAT EXCHANGER Filed June 21, 1961 2 Sheets-Sheet 1 F "L H i INVENTOR.

W4 irroe/vzr 1955 I H. R. o'r'ro 3,212,572

PLATE TYPE HEAT EXCHANGER Filed June 21. 1961 2 Sheets-Sheet 2 Fig-1U United States Patent 3,212,572 PLATE TYPE HEAT EXCHANGER Howard R. Otto, Dayton, Ohio, assignor to United Aircraft Products, Inc., Dayton, Ohio, a corporation of Ohio Filed June 21, 1961, Ser. No. 118,613 13 Claims. (Cl. 165166) This invention relates to plate type heat exchangers, and particularly to new structural concepts in such devices whereby they may be made easier and cheaper to build while retaining or improving upon reliability and strength characteristics.

To provide a plate type heat exchanger so characterized is a leading object of the invention. In accordance with features of the invention the heat exchanger is basically built up through repeated use of parts of identical construction, and provision is made for a flexible kind of fabrication in which a strip fin material used in the flow passages may be suitably compressed to assure good contact between the elements of the exchanger, and, therefore, further assuring a strong bond in the uniting of the elements into an integrated assembly.

Other objects and structural details of the invention will appear more clearly from the following description, when read in connection with the accompanying drawings, wherein:

FIG. 1 is a fragmentary view in perspective of the core of a plate type heat exchanger constructed in accordance with the illustrated embodiment of the invention;

FIG. 2 is a fragmentary view of the article of FIG. 1, in side elevation;

FIG. 3 is a fragmentary side view, enlarged with respect to FIGS. 1 and 2, of one end of a plate element used in construction of the heat exchanger;

FIG. 4 is a detail view in side elevation of the plate element of FIG. 3;

FIG. 5 is a detail view in end elevation of the plate element of FIG. 4;

FIG. 6 is a fragmentary view like FIG. 3, showing a section of the heat exchanger plate, the view being taken from one end of the plate as in FIG. 5, and the abutting relationship achieved with a companion plate being indicated in dotted outline;

FIG. 7 is a fragmentary detail View of a pair of plates shown in superposed position prior to the applying of compression thereto preliminary to the uniting of the parts;

FIG. 8 is a detail view of a pair of plates in superposed position showing the manner in which adjacent plates are oriented relatively to one another in the assembly of the exchanger;

FIG. 9 is a view like FIG. 8 showing the parts brought into mating contacting relation; and

FIG. 10 is a detail fragmentary view of one end of a plate made in accordance with an alternate form of the invention.

Referring to the drawings, the core of a plate type heat exchanger conventionally is a fabricated device made up of a plurality of different elements including plates, strip fins and various forms of spacing and connecting devices. In accordance with the instant inventive concept a heat exchanger core is fabricated using multiple elements of identical configuration, plus such inserted strip fin means as may be necessary or desirable. The single element of which the heat exchanger core essentially is comprised is a plate 10 suitably formed and cooperating with other such plates to form a structure defining the separated, relatively angularly disposed flow passageways characteristic of a plate type exchanger.

3,212,572 Patented Oct. 19, 1965 While the plates 10 may be constructed of any suitable material, and formed in any convenient manner, they are in the illustrated instance made of sheet metal and stamped or similarly pressed and formed to assume the desired configuration. Thus, as constructed, each plate 10 is formed with a rectangular and generally flat body portion 11. Near both opposing ends the plate is turned over and defines unitary end walls 12 at right angles to the body 11. At their extremities the turned over end walls 12 are bent inwardly toward one another to define tips 13 disposed in spaced relation to the body 11 on one side thereof. On its other side the body portion 11 is recessed, there being formed therein a large recessed area 14 which at its ends extends to the side walls 12 and which at its sides extends short of the opposing side edges of the plate in a manner to define marginal lands 15 along such opposing side edges.

In the assembly of the heat exchanger core, the plates 10 are stacked one upon another With adjacent plates being relatively inverted. Thus, and as indicated in FIGS. 1 and 2, a lowermost plate of the assembly may have its end walls 12 extending upwardly in which case the next adjacent plate is reversely disposed, with the two plates being so oriented as to be in superposed aligned relation with inwardly bent extremities 13 in contacting relation to one another. Above the second described plate a third plate is laid in superposed relation to the first two and in relatively inverted relation to the second. Thus the third plate presents its marginal lands 15 in opposing relation to the corresponding lands on the said second plate and the plate elements are so oriented as to locate the marginal lands of such adjacent plates in contacting aligned relation. The stacking of plates in this manner is continued until the number of assembled plates is adequate to provide flow area and heat transfer surface as contemplated by the design specifications. Suitably held in a fixture, the assembly of plates then is brazed or otherwise interconnected to form an integrated unit. The areas of contact as represented by the abutting extremities 13 and by the abutting marginal lands 15 represent joints or seams along which the adjacent plates are bonded together in a manner securing such plates rigidly together as well as providing a fiuid tight seal.

The described construction is such as to define in the core interior a first series of flow passages 16, represented by each pair of plates joined at the extremities 13, and further to define other passages 17 which are at right angles to the passages 16 and defined by mating recessed areas 14. The arrangement places the passages 16 and 17 in alternating relation to one another in such manner that different fluids passing through such separated flow passages are in heat transfer relation through the material of the plates 10 and particularly through the bodies 11 thereof. Assisting in the function of absorbing and transmitting heat in the device are metallic strip fin means 18 installed in the flow passages 16 and other strip fin means 19 installed in the flow passages 17. The strip fin means conventionally has a corrugated or crimped configuration providing peaks and valleys in contact with adjacent plate surfaces in such manner as to conduct heat directly to and from such surfaces. In accordance with a preferred form of plate type heat exchanger construction, the strip fin devices are installed in their respective passages prior to the brazing or interconnecting of the plates into an integrated unit and are in the course of such process likewise brazed or secured to the contacting plate surfaces. The result is to assure positive, continued contact of the fin means with the plates as Well as to provide multiple ties between adjacent plates intermediate their margins whereby to strengthen the heat exchanger and materially to increase its resistance to the stresses of fluid pressure.

. the plate a relatively elevated surface 21.

face 21.

The recessed area 14 of each plate is achieved by in effect depressing an area of the plate intermediate the marginal flanges 15 and intermediate the turned over ends 12. The result is to form on the reverse side of Opposing surfaces 21 on adjacent plates provide the contact or seating surfaces for the interposed peaks and valleys of the strip fins 18. According to a feature of the invention the extremities 13 are flexible in construction and normally incline slightly outward or away from the plane of sur- When the extremities of adjacent plates are initially brought together they tend to maintain their original inclination in approximately the manner indicated in FIG. 7. When the strip fin means has been installed between the plates, however, the several superposed plates are subjected to a clamping force compressing the bent extremities 13 to accomplish a full contacting engagement of adjacent extremities, and, in so doing, to form joints, as seen in FIG. 2, which are parallel to the surfaces 21. The movement of the plates compressing the extremities 13 is in effect a lost motion by which not only are the adjacent bent extremities brought into firm engagement with one another but also by which the surfaces 21 are made uniformly to contact the peaks and valleys of the fin means 18 along the entire length thereof. Thus no interruption of the joint defined by each such peak and valley with its engaged plate surface is possible and opportunity for localized yield to fluid pressures is avoided. The strip fin means 18 is constructed of relatively thin, foil-like material which may itself yield where necessary to accommodate a full compression of the plate assembly as described.

The heat exchanger core is thus made up of a plurality of identical plate elements 10 and may include the separate strip fin means 18 and 19. A core as illustrated is fabricated using only three different parts, selected in multiples as required, these being a plate 10, a strip fin 18 and a strip fin 19.

The plates 10 are, as described, rnade preferably of thin sheet metal for simplified forming and good heat transfer characteristics. For better strength and resistance to damage and pressure deformation the plates may in regions be reinforced. As shown in FIG. 10, a plate 22 having a body portion 23 and turned over end wall 24 has an extremity 25 made thicker than the extremities 13 of the FIGS. 1 to 9 embodiment by having a portion thereof turned back upon itself. The joint effected by bringing adjacent extremities 25 into contacting relation to one another accordingly is heavier, stronger and more resistant to attempted separation and deformation.

While in the illustrated instance only the extremity 25 has been given a double thickness, the reversely bent portion could be extended to overlap more or less of the end wall 24 as might be desirable. Similarly, longitudinal side edges of the plate body 11, at the location of the lands 15, may be reversely bent upon themselves to define heavier joints of added damage resistance.

What is claimed is:

1. For use in a plate type heat exchanger, a plate having a recessed area on one side defining marginal lands along opposing side edges of the plate on said one side thereof, the ends of said plate being turned over at right angles to said plate to ext-end through and beyond the plane of the opposite side of the plate, said recessed area opening through the turned over edges of the plate in advance of said ends to terminate in the plane of said turned over ends, and means on said turned over ends providing a broadened contact area.

2. A plate according to claim 1, characterized in that said last named means is defined by extremities on said turned over ends bent inwardly into generally opposing relation to one another in spaced relation to the said opposite side of said plate.

3. For use in a plate type heat exchanger, a plate having a recessed area on one side defining marginal lands along opposing side edges of the plate on said one side thereof, the ends of said plate being turned over to extend through and beyond the plane of the opposite side of the plate, said recessed area opening through the turned over edges of the plate in advance of said ends, and extremities on said turned over ends bent inwardly into generally opposing relation to one another in spaced relation to the said opposite side of said plate, said extremities inclining away from said plate and being resilient for compression to a position approximately parallel to said opposite side of the plate.

4. A plate type heat exchanger, including a plate having a recessed area on one side defining marginal lands along opposing side edges of the plate on said one side thereof, the ends of said plate being turned over at right angles to said plate to extend through and beyond the plane of the opposite side of the plate, said recessed area opening through the turned over edges of the plate in advance of said ends to terminate in the plane of said ends, plate means extending across and joining said turned over ends, said plate means being in spaced parallel relation to said plate and defining therewith a through flow passage for fluid to move in heat transfer relation to said plate on the said opposite side thereof, other plate means in superposed relation to said plate in contacting relation to said marginal lands and bridging said recessed area to define a flow passage at right angles to the first said passage for fluid to move in heat transfer relation to said plate on the said one side thereof, and means for securing said other plate means to said marginal lands, said lands serving the dual purpose of spacing said other plate means from said recessed area of said plate and of attaching said other plate means to said plate.

5. A plate type heat exchanger according to claim 4, characterized in that said plate means are plates constructed like the one said plate and brought into contacting superposed relation as described and occupying relatively inverted positions.

6. A plate type heat exchanger, including plates each having a recessed area on one side defining marginal lands along opposing side edges on said one side, the ends of the plate being turned over to extend through and beyond the plane of the opposite side of said plate, the extremities of said ends being bent inward toward one another in spaced relation to the said opposite side of said plate, said plates being in superposed relation to one another and in alternately inverted attitudes to define alternating separated flow paths through the heat exchanger at right angles to one another, and means joining said plates in an integrated structure, mating marginal lands on adjacent plates and mating extremities on adjacent plates defining joints closing the sides of respective flow passages, said means joining said plates bonding said plates together along said marginal lands and along said extremities to seal said defined joints.

7. A plate type heat exchanger comprised of a plurality of identical plates stacked one upon another to define alternating flow passages at right angles to one another, each of said plates having on one surface thereof raised marginal lands along opposing side edges and being turned down at its ends with the extremities of said ends bent inward toward one another in spaced relation to the other surface of the plate, adjacent plates being relatively inverted to place the bent extremities of one plate in contact with corresponding extremities of an adjacent plate on one side thereof and to place the marginal lands of said one plate in contact with corresponding marginal lands of an adjacent plate on the other side thereof, and means securing the stacked plates into an integrated assembly, said means joining said plates together :along said marginal lands and along said extremities.

8. A plate type heat exchanger according to claim 7, characterized in that the bent extremities of each of said plates normally incline away from the said other Surface of the plate, an assembly of stacked plates being compressible to bring said extremities approximately parallel to the bodies proper of said plates.

9. A plate type heat exchanger according to claim 8, characterized by strip fin means installed in at least some of said flow passages, said assembly of stacked plates being compressible as described to achieve a uniform contacting relation of the plates to the peaks and valleys of said strip fin means.

10. A plate type heat exchanger according to claim 7, characterized in that each of said plates is formed with a multiple thickness of material at the location of said bent extremities for a reinforced joint along said extremities.

11. A plate type heat exchanger according to claim 7, characterized in that each of said plates is formed with a multiple thickness of material at the location of at least some of the surfaces along which the plate contacts other adjacent plates.

12. A plate type heat exchanger comprised of a plurality of identical plates stacked one upon another to define alternating flow passages at right angles to one another, strip fin means installed in at least some of said flow passages, each of said plates having on one surface thereof raised marginal lands along opposing side edges and being turned down at its ends with the extremities of said ends bent inward toward one another in spaced relation to the other surface of the plate, adjacent plates being relatively inverted to place the bent extremities of one plate in contact with corresponding extremities of an adjacent plate on one side thereof and to place the marginal lands of said one plate in opposing relation to corresponding marginal lands of an adjacent plate on the other side thereof, said bent extremities of each of said plates normally inclining away from the said other surface of the plate whereby to allow assembly of said plates and of said strip fin means without contact of the marginal lands of adjacent plates with one another, the assembly being compressible to bring said extremities approximately parallel to the bodies proper of said plates and in the process to achieve a uniform contacting relation of the plates to the peaks and valleys of said strip fin means and to engage the marginal lands of adjacent plates.

13. A plate type heat exchanger according to claim 12 characterized by means for uniting said plates to one another along said engaged marginal lands and along the defiected interengaged bent extremities of said plates.

References Cited by the Examiner UNITED STATES PATENTS 2,368,814 2/45 Fagan 166 2,462,421 2/49 Pitt 165166 X 2,553,030 5/51 Bell 165-166 2,912,749 11/59 Bauernfeind et a1 165167 2,959,401 11/60 Burton 165166 FOREIGN PATENTS 655,470 7/51 Great Britain.

CHARLES SUKALO, Primary Examiner.

HERBERT L. MARTIN, PERCY L. PATRICK,

Examiners. 

1. FOR USE IN A PLATE TYPE HEAT EXCHANGER, A PLATE HAVING A RECESSED AREA ON ONE SIDE DEFINING MARGINAL LANDS ALONG OPPOSING SIDE EDGES OF THE PLATE ON SAID ONE SIDE THEREOF, THE ENDS OF SAID PLATE BEING TURNED OVER AT RIGHT ANGLES TO SAID PLATE TO EXTEND THROUGH AND BEYOND THE PLANE OF THE OPPOSITE SIDE OF THE PLATE, SAID RECESSED AREA OPENING THROUGH THE TURNED OVER EDGES OF THE PLATE IN 